KUKA 1FK7081-5AZ91-1ZZ9-Z Encoder Pinouts

you would need to decode the motor part number to see exactly what kind of encoder that is. Siemens has long list of options.

Quote from RustyRSA

Dear Forum,

I have a KUKA Motor (Siemens 1FK7081-5AZ91-1ZZ9-Z) which I want to test with a Panasonic Drive (MDBLN25SG) and interface the drive to a MASSO G3 controller.

I'm trying to mate the Encoder connections of the KUKA Motor to the Panasonic drive.

Siemens motor encoder has these 12pin connections - no clue what these mean.

pin1-S2, pin2-S4, pin7-R2, pin8-+1R1, pin9-1R2, pin10-R1, Pin11-S1, pin12-S3

Panasonic drive encoder has these connections - these are easy.

pin1-E5V, pin2-E0V, pin5-PS, pin6-PS(not)

The Panasonic documentation is very good but I can't for the life of me find any reference of what the Kuka/Siemens motor signals mean.

I need to connect these two units together.

Please can someone enlighten me.

Many thanks

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Siemens motor encoder has these 12pin connections :

may you say what is the function of pins 3-4-5-6 ?

if that is a KUKA motor - why not post KUKA label? this forum is about KUKA products, not Siemens products. Siemens makes a lot of other variants and one can get motor with some 19 possible position sensor types and 50 different temperature sensor options... if i remember right that is encoded into second part of the Siemens part number. feel free to download and reed Siemens servo catalog which i don't have at hand...

anyway, Google search did confirm that this is a KUKA motor - MG_110_130_40_S0 or article number 00-121-216. Very good...

This resolver connector is 12-pos.There are 4 twisted pairs individually shielded:

+ motor temperature,

+ resolver primary (used for excitation)

+ resolver secondary (SIN)

+ resolver secondary (COS)

That is 8 contacts... remaining four that you refer to (positions 3,4,5,6) are used for those four shields.

Note that those four positions are always populated and connected to RDC box but is common that they are not connected (contacts not even populated) on the motor side... And sometimes they are connected all the way through.

If you have a motor feedback cable that is an extension, then those four positions are connected through - this way shield is continuous all the way from RDC box towards the motor. But if cable is not an extension, just a normal motor feedback cable, then shields are simply not connected at the motor end. And that is why you can order both types of feedback cable from KUKA - with and without shields terminated at the far end (going towards motor).

So someone may notice that KUKA motors normally do not even have those pins on the resolver connector populated, it is tempting to only use/stock the fully terminated 1:1 cable version (the extension). It may cost a bit more but less than keeping track of cable types, or stocking both and you know someone will mix them up sooner or later. But now you know how to check - those pins may be missing, otherwise try continuity check.

Some other tips and notes:

It turns out that shield (a conductive barrier placed close to core, separating core and environment) is good for blocking interference from electric field, but... it does very little when it comes to magnetic field. And also magnetic field effects are strong - but only at short range. Very little distance does a lot to weaken magnetic strength. And this is why there are tray and panel dividers between different sections (signal/power/EOAT)

Solution to avoid interference? Use shielded cable to prevent noise from getting in OR getting out of the cable and - have the shield grounded.

For signal cables sources of interference are outside (in the environment, not in the cable) and it is very common that shield is only grounded at one end as this prevents "ground loops". In other words current flow through shield along the sensitive signal conductors is eliminated... Another measure to increase immunity is to use differential pair (twisted pair) inside shield. each twisted pair has own shield. Sometimes cables will also have another overall shield but this is not common in robotics since it limits cable flexibility.

For power cables (think VFD, servo, any inverter or PSU specially switching mode) source of interference is inside the circuit and shield is used to minimize effects of the noise (produced by mentioned circuit) on the environment and whatever may be nearby. in this case ground loops are not as big of a concern (they mean loses) but using everything to reduce impedance between two cable ends will make better "short circuit" and thus help dampening any interference that tries getting out.

And... there is another case... Some motors (non KUKA), such as in some spot welding guns may have noisy feedback due to particular motor construction. For them to work properly it may be better that those four shields are connected all the way through - even at the Motor end (from RDC to resolver). In that case additional external grounding conductor of large cross section is required (and in many cases it is already there). Without it there would be a ground loop so that axis would be unstable. Current takes path of least resistance and external large cross section conductor (standard is 16mm²) is low impedance even at high frequencies (skin effect). Also even if this cable is laid inside energy supply wrapped around the robot, proximity of that conductor and the signal cores in feedback cable is considerably larger than distance between those sores and own shield... Which is why large ground conductors are so essential in applications that use tooling with high power and high frequency (anything using inverters - arc welding, spot welding, plasma cutting...). here "high" frequency is referred to anything that is higher frequency than mains (by one or more orders of magnitude). Basically anything in the ballpark of 500Hz or higher is deemed high enough...

Note that inverters/VFDs/servos operate usually in several kHz range, often 8 or 16kHz.

Additionally those are often high power (both high voltage and high current). So those high frequencies (and skin effect) are the reason why GND conductor in mains cable (in X1 connector for non-Americans) is often inadequate... Applications dealing with high frequency tools require additional GND conductors:

+ from EOAT to robot foot.

+ from robot foot to KRC

+ from KRC to local GND (building).

etc.

KUKA asks for low impedance (0.1Ohm or better if I recall) in frequency range DC - 3GHz.

it is not enough to know the pinout... one must know full electrical spec of the interface(s).

it is clear that the two devices have very different type of feedback.

what is the reason to use Panasonic drive in KRC? Why not use KRC drive?